We assessed the feasibility of transplanting a sheet of retinal pigment epithelial (RPE) cells differentiated from induced pluripotent stem cells (iPSCs) in a patient with neovascular age-related macular degeneration. The iPSCs were generated from skin fibroblasts obtained from two patients with advanced neovascular age-related macular degeneration and were differentiated into RPE cells. The RPE cells and the iPSCs from which they were derived were subject to extensive testing. A surgery that included the removal of the neovascular membrane and transplantation of the autologous iPSC-derived RPE cell sheet under the retina was performed in one of the patients. At 1 year after surgery, the transplanted sheet remained intact, best corrected visual acuity had not improved or worsened, and cystoid macular edema was present. (Funded by Highway Program for Realization of Regenerative Medicine and others; University Hospital Medical Information Network Clinical Trials Registry [UMIN-CTR] number, UMIN000011929 .).
The generation of induced pluripotent stem cells (iPSCs) provides the opportunity to use patient-specific somatic cells, which are a valuable source for disease modeling and drug discovery. To promote research involving these cells, it is important to make iPSCs from easily accessible and less invasive tissues, like blood. We have recently reported the efficient generation of human iPSCs from adult fibroblasts using a combination of plasmids encoding OCT3/4, SOX2, KLF4, L-MYC, LIN28, and shRNA for TP53. We herein report a modified protocol enabling efficient iPSC induction from CD341 cord blood cells and from peripheral blood isolated from healthy donors using these plasmid vectors. The original plasmid mixture could induce iPSCs; however, the efficiency was low. The addition of EBNA1, an essential factor for episomal amplification of the vectors, by an extra plasmid greatly increased the efficiency of iPSC induction, especially when the induction was performed from abT cells. This improvement enabled the establishment of blood-derived iPSCs from seven healthy donors ranging in age from their 20s to their 60s. This induction method will be useful for the derivation of patient-specific integration-free iPSCs and would also be applicable to the generation of clinical-grade iPSCs in the future. STEM CELLS 2013;31:458-466 Disclosure of potential conflicts of interest is found at the end of this article.
SummaryDuchenne muscular dystrophy (DMD) is a severe muscle-degenerative disease caused by a mutation in the dystrophin gene. Genetic correction of patient-derived induced pluripotent stem cells (iPSCs) by TALENs or CRISPR-Cas9 holds promise for DMD gene therapy; however, the safety of such nuclease treatment must be determined. Using a unique k-mer database, we systematically identified a unique target region that reduces off-target sites. To restore the dystrophin protein, we performed three correction methods (exon skipping, frameshifting, and exon knockin) in DMD-patient-derived iPSCs, and found that exon knockin was the most effective approach. We further investigated the genomic integrity by karyotyping, copy number variation array, and exome sequencing to identify clones with a minimal mutation load. Finally, we differentiated the corrected iPSCs toward skeletal muscle cells and successfully detected the expression of full-length dystrophin protein. These results provide an important framework for developing iPSC-based gene therapy for genetic disorders using programmable nucleases.
We examined the gene expression and DNA methylation of 49 human induced pluripotent stem cells (hiPSCs) and 10 human embryonic stem cells and found overlapped variations in gene expression and DNA methylation in the two types of human pluripotent stem cell lines. Comparisons of the in vitro neural differentiation of 40 hiPSCs and 10 human embryonic stem cells showed that seven hiPSC clones retained a significant number of undifferentiated cells even after neural differentiation culture and formed teratoma when transplanted into mouse brains. These differentiation-defective hiPSC clones were marked by higher expression levels of several genes, including those expressed from long terminal repeats of specific human endogenous retroviruses. These data demonstrated a subset of hiPSC lines that have aberrant gene expression and defective potential in neural differentiation, which need to be identified and eliminated before applications in regenerative medicine.
Full-length cDNA (FLcDNA) libraries consisting of 172,000 clones were constructed from a two-row malting barley cultivar (Hordeum vulgare 'Haruna Nijo') under normal and stressed conditions. After sequencing the clones from both ends and clustering the sequences, a total of 24,783 complete sequences were produced. By removing duplicates between these and publicly available sequences, 22,651 representative sequences were obtained: 17,773 were novel barley FLcDNAs, and 1,699 were barley specific. Highly conserved genes were found in the barley FLcDNA sequences for 721 of 881 rice (Oryza sativa) trait genes with 50% or greater identity. These FLcDNA resources from our Haruna Nijo cDNA libraries and the full-length sequences of representative clones will improve our understanding of the biological functions of genes in barley, which is the cereal crop with the fourth highest production in the world, and will provide a powerful tool for annotating the barley genome sequences that will become available in the near future.
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